The effects of acidified pepsin on porcine vocal fold tissue: Developing a porcine model of laryngopharyngeal reflux disease

Approximately 7.5 million Americans are affected by a voice disorder. In the last year, 7.2% of people missed one or more days of work due to a voice problem. For professional voice users, such as teachers, the rate increases to 20% and an annual cost of $2.5 billion. Voice disorders are complex and multi-faceted, as well as difficult to diagnose and treat. Prospective animal studies are necessary to study the pathophysiology of voice disorders, optimize our understanding of laryngeal pathology, and improve treatment outcomes. The pig provides a unique opportunity to test hypotheses relating to laryngeal disease because porcine vocal folds are most similar to human vocal folds from a structural, biochemical, neuromuscular, and cellular perspective. By utilizing the pig as a model of laryngeal disease, research involving basic, translational, and clinical questions can be investigated through collaborations with experts in the field. This dissertation will present ex vivo and in vivo data utilizing pig tissue to study a common voice disorder, laryngopharyngeal reflux. Ex vivo pig tissue was challenged with acidified pepsin in different electrolyte environments to test the innate defense mechanisms of the vocal fold epithelium. From there, an in vivo pig model was designed to mimic the clinical situation of human LPR more closely by challenging healthy, uninjured laryngeal epithelia with acidified pepsin. The data suggests that healthy vocal folds are able to defend effectively against reflux challenges. Future plans are to utilize a similar model to investigate other common laryngeal diseases that afflict the human population as well as therapeutic interventions to these disorders